The Optimal inter-implant interval in pediatric sequential bilateral implantation

An increasing number of children receive bilateral cochlear implants (CIs) sequentially. Outcomes of bilateral implantation show high variability. This retrospective analysis investigates the optimal inter-implant interval. For this purpose, speech comprehension results of 250 children who underwent sequential bilateral cochlear implantation were evaluated. All individuals underwent periodic speech perception testing in quiet and noise. The most recent unilateral data for each side were statistically analyzed. Speech test outcomes were evaluated with reference to age at first implantation and interval between implantations. A statistically significant difference for speech test performance was obtained between the first-implanted ear and the second-implanted ear for all children (expressed as a mean). These outcomes were dependent on the inter-implant interval. There was a significant correlation (r = - 0.497; p = 0.000) between speech test results and the inter-implant interval. Nevertheless, one subgroup of 27 children had the same or better results for the second side as compared with the first. In conclusion, the evaluation of the inter-implant interval and age groups at first implantation showed a preferred interval of up to four years in children under the age of 4 at first implantation. The older the children were at first implantation, the shorter the inter-implant interval had to be. It is as a direct consequence of this interval that children for whom it was longer were also older.